At present, in order to impart flame retardancy to laminates, the formulation in combination with the brominated flame retardants is used. However, in recent years, more and more attentions have been paid to the environmental problems, and it is desirable to use the resin compositions containing no halogen compound to further study the phosphorus compounds which can replace the halogen-containing flame retardants. However the phosphorus compounds may also produce toxic compounds such as phosphine, etc. when burned, therefore it is extremely urgent to develop laminates containing no halogen and phosphorus compounds and having excellent flame retardancy.
Although ordinary FR-4 laminates and copper-clad laminates have flame retardancy and self-extinguishing when burned in the fire, the burning residues have no mechanical strength and become ashes after continuous high temperature combustion, the integrity of the articles cannot be maintained as well, even more dangerous secondary disaster may be caused, which will result in short circuit, thus they cannot be used in the fields of high fire resistance and high heat resistance.
The ceramic silicone resin laminate exhibits excellent properties of ordinary silicone resin at room temperature. However, it can be converted into a complex ceramic structure at high temperature to have ceramic properties, and becomes a hard self-supporting ceramic product with a certain strength, which can withstand a certain impact force, and can also maintain the integrity of the laminates when ablated in open flames at 1000° C. or more, so as to isolate the reaction of the internal materials under the surrounding high temperature, which can play a better fire resistance and flame retardancy role and guarantee the smooth of electricity and communication during the fire.
Silica in a powdered form will be generated when the silicone resin burns at high temperature. However, after a silicate-based fire-resistant filler (mica, wollastonite, and kaolin, etc.) is added, the silica generated by the decomposition of the silicone resin may react with the fire-resistant filler and form an “eutectic mixture” at the edge of the filler to play a bridging role between the silica particles and filler particles, which is solidified at the ignition temperature, and an agglomerated ceramic product can be formed when cooling. This ceramic body has self-supporting property, and is able to withstand a certain mechanical shock and vibration, which can be used as thermal protection materials, heat-resistant wave-transmitting and absorbing integrated materials or other functional laminates with high temperature requirements.
The ceramic silicone resin laminate has the advantages of excellent electrical properties, good thermal shock resistance, halogen-free, low smoke, low toxicity, self-extinguishing and environmental protection, etc. The present invention provides new ideas and new methods in terms of flame retardancy and fire resistance to accelerate the development of research on the passive fire resistance technology of laminates, which have broad prospects in the fields of flame retardancy and fire resistance.